Wire matrix printer



Aug. 3, 1965 R. A. BACHMAN WIRE MATRIX PRINTER 3 Sheets-Sheet 1 FiledMarch 28, 1962 TIN [l H M Aug. 3, 1965 R. A. BACHMAN WIRE MATRIX PRINTER3 Sheets-Sheet 2 Filed March 28, 1962 Dacoooo I NVENTOR. 055.67' 4.E40/MAN Aug. 3, 1965 R. A. BACHMAN WIRE MATRIX PRINTER 3 Sheets-Sheet 5Filed March 28, 1962 FIE E INVENTOR. ,055,97 A. BAU/M4N Robert A.Eachrnan, La Crescenta, Calif., assigner to` Ciary Corporation, ofCaiifornia Filled Mar. 28, 1962, Ser. No. 14,639 12 Ciaiins. (Ci. 197-1)San Gahriei, Calif., a corporation wire matrix type, such as thatdisclosed in U.S. Patent .2,129,065 to Joseph N. Loop, employed acharacter forming series of individually operable dot print elementswhich are simultaneously projected in combination against an ink ribbonto etfect printing of a whole character at once.

Such print heads have herebefore had such high mass that at high speedsit became impractical to use this type i of print head for serial lineprinting where the head is stepped along the print line.

Therefore the principal object of the invention is to provide a printhead of such light mass that it becomes practical to shift the headalong a print line at high speeds.`

Another object is to provide a print head and actuating means requiringa minimum number of moving parts.

Another object is to provide a print head which is inexpensive tomanufacture and assembie.

A still further object is to provide a novel clutching means forpositively moving the print head accurately at high speeds, transverselyalong the print line in equal increments.

Other objects and structural details of the invention will be apparentfrom the following description when read in connection with theaccompanying drawings, in which:

FIG. l is a top plan view illustrating a printer embodying a preferredform of the present invention.

FG. 2 is a sectional side view of the printer taken substantially alongthe line 2 2 of FIG. l.

FIG. 3 is an enlarged view of one of the several guide plates which formthe print head.

FIG. 3A is a side view of certain of the guide plates and is taken alongline 3A3A of FIG. 3.

FIG. 3B is a transverse sectional view through a guide plate and istaken along line 3B-3B of FIG. 3.

FG. 4 is a longitudinal sectional view through the carriagc mechanismfor the print head and is taken substantially along the line 4 4 of FIG.2.

FIG. 5 is a transverse `sectional View taken along the line 5-5 of FIG.4.

FIG. 6 is a transverse sectional view of the clutch and is taken aiongthe line 6 6 of FIG. l.

FIG. 7 is a typical elevational view of a guide roller forthe actuatingWires and is taken along theV line 7--7 of FIG. l.

FIG. 8 is a sectional plan viewthourgh one of the wireactuators and istaken along the line 3--8 of FIG. 2. FIG. 9 is a sectional elevationview of an alternate mechanism for actuating the printer wires.

FIG. l0 is a longitudinal lsectional view with parts broken away and istaken along the line `lit-1t) of FIG. 9. The matrix pattern for thisprinter is preferably made up of tive vertical columns of seven dotseach which, upon proper selection, will print all the letters of thealphabet and the ten decimal numerical digits as well as most commonlyused symbols.

The print head assembly, generally indicated at 51 in FIGS. l and 2,comprises seven identically formed guide aired states Patent O lCCplates 52, one of which is shown in detail in FIGS. 3 and 3A. p

Each guide plate 52 is formed of a plastic material having highelasticity characteristics, such as that known in the art as Delrin, andhas` guideways 53 formed therein, which are recessed slightly deeperthan the diam- F which tails are formed integrally with the body of theplate 52. Each tail has two projecting studs 58 and 59 thereon whichextendperpendicular to the plane of the plate 52 and terminate at thetop surface plane of the same. The studs form an opening 60 therebetweenwhich is slightly larger than the diameter of the wire 55.

Each plate 52 has a second set of guideways 61 which are recessedapproximately twice the depth of the guideways 53 and which follow anarcuate path through the plate 52.

A second or actuating section 63 of each of the wires 55, enters theplate 52 through a respective guideway 61, passing into an opening 56and through the openings 60 formed by the studs 5ft and 59 of therespective tail. The wire is then looped around the stud 58 andthereafter passes back over itself. This contsruction enables a directpull on each wire to be transferred to a direct endwise pushing actionon the respective print head section.

As `shown in FIGS. 2 and 3A, the plates 5.2 are wedge shaped so thatupon final assembly the head will be wedge shaped whereby the wires 55will converge at a point in i front of the head thereby formingdifferent character `patterns upon striking a sheet of paper 200 locatedat a printing station whereat it extends over a cylinder type platen 64.

The plates 52 are interlocked with one another through tits 65 formed onthe top surface of the plates and cups 56 formed on the lower surfaces.This assembly is then slipped into a wedge shaped frame 67 formed of alight material such as plastic. Bolts 63 pass through holes in the frameand through respective holes 69 in the plates 52, clamping the plates inthe frame.

The frame 67 has formed on its upper cover a iiexible arm 71 having abearing cup 72 integrally formed at its end which carries a bearing ball72.

The lower cover of the frame 67 has integrally formed thereon a rigidarm 74 having a bearing cup 75 which carries a bearing ball '76.

The balls 73 and 76 ride in rigid guideways formed in cross members 77and '78, respectively, which are rigidly fixed to side frames 14 Vand15, `for guiding the head 51 axially along the platen. The members 77and 78 also have formed therein shallow cups 81 which are equally spacedand aligned with the print spacing of a page. As the bearing ballsengage such cups they tend to detent the head in printing position.

The drive mechanism comprises a continuously rotating shaft 11,supported in a pair of bearings `12 and 13 (FIG. l) fixed in the machineside frames 14 and 15, respectively, the shaft being driven by a motor(not shown) through a gear 16. t

The shaft 11 has a plurality of circumferen-tially ex- A tudinally alongthe shaft 11 upon engagement of the clutch, as will be described laterwhereby to advance the print head.

The driving side of the clutch assembly is comprised of a hub 19 whichis slideably keyed to the shaft 11 at 21, through longitudinally alignednotches 22 in rack teeth 23.

The driven side 'of the clutch is comprised of a hub 24 slideablymounted on the teeth 23 of the shaft 11, by a bearing surface 25. 1n theleft hand end of the hub 24 is a cavity 26 having a little more than onefull spiral or helical thread 27 formed coaxially of the shaft 11. Thepitch of the thread 27 is equal to the spacing between centers of thecircular teeth 23.

A gear 28 is iitted in a slot 29 in the end of a shaft 31 and isrotatably mounted on a cross pin 32 carried by the shaft and extendingtransversely to the axis of the shaft. The gear normally meshes with thethread 27 and with the anges 23 of the shaft 11. The shaft is rotatablymounted in bearings formed in arms 88 carried by the print head 52 andis suitably prevented from axial movement relative to the print head andclutch.

The clutching mechanism is similar in operation to that disclosed in US.Patent No. 2,700,421 to E. O. Blodgett in which a helically woundexpansion clutch spring 33 is wound to surround a sleeve portion 34 ofthe hub 19 as well as a sleeve portion 35 of the hub 24, the sleeves 34and'35'being ofthe `same diameter.

One end of the spring 33 is attached to the sleeve 35 by a pin 36 whilethe opposite end of the spring is attached by a pin 3S to a sleeve 37,the latter surrounding the spring 33 and associated sleeves 34 and 35.

The outer peripheral face of the sleeve 37 (FIG. 6) has a latch shoulder39 which normally abuts a clutch dog 41. The latter prevents the sleeve37 from rotating and thus holds the spring slightly expanded to releaseits grip on the sleeves 34 and 35.

. The clutch dog 41 forms an integral part of the armature 42 of anelectromagnet 43. The armature is pivotally supported at 87 on a magnetframe S5 and is normally urged into contact with the shoulder 39 of thesleeves 37 by a tension spring 40.

An anti-backup latch 44 (FIG. 5) is pivotally supported by a bracket 45and is normally urged into engagement with the outer periphery of thehub 24 by a tension spring 47. The latch 44 cooperates with a latchshoulder 48 on the hub 24, to allow overthrow of the sleeve 35 a slightamount, as above described, before latching to prevent the sleeve fromrotating clockwise and thus to maintain the spring clutch disengaged.

The magnet frame S and bracket 45 are carried by a housing 46 attachedat one end to one of the arms 88 of the print head 51 by bolts 49. Atits opposite end the housing has a collar 92 which is guided over theshaft 11.

A guide rod 93 directly below the shaft 11 is suitably attached to theside frames 13 and 14 and extends through bearing holes in the arm 8Sand housing 46 to prevent the housing 46 from rotating.

The print wires 55 which pass out of the grooves 61 of the print head 51pass around four sets of guide posts 95 (FIGS. l and 7) and are returnedto the opposite side of the print head, where they are suitably attachedto a plate 95 on the print head.

The posts 95 are comprised of bolts 98 which are anchored between amachine base plate 99 and to one of two respective plates 101. Thelatter are in a plane parallel with the base plate and are attached torespective side frames 14 and 15. FIG. 1 shows only the plate 101attached to side frame 14, the other plate 101 being removed forclarity.

A rotatable sleeve 102 is positioned on each bolt 98 intermediate theplates 99 and 161, and has formed therein seven grooves 193 which areslightly wider than the wire diameter, for guiding the wires.

The means for actuating the wires 55 to achieve a print is shown inFIGS. l, 2 and 8 wherein the wires 55 pass through holes 104 in endplates 105 and 166 of respective enclosed containers 107 and 198. Thelatter are supported through legs 11ti9 by the base plate 99.

Since the containers 197 and 16S are the same in structure and operationexcept for different wire actuation, -only the container 108 will bedescribed in detail. Solenoids 109, one for a respective wire 5S, aremounted about the periphery of the container 19S inra prescribed mannersuch that wire links or leads 111 from the armatures 112 of thesolenoids 109 to respective wires 55 can transversely deflect such Wireswithout interfering with other wires.

The leads 111 are not connected directly to the wires 55, but insteadare connected to small tubes or ferrules 113 surrounding respectivewires so that upon energizetion of a solenoid 109, a corresponding wirewill be bowed between end plates 1% as indicated by the dotted lines 114(FIG. 8).

It should be understood that there are thirty five solenoids 109, onefor each of the lines 55, and that they are distributed between thecontainers 1117 and 1118 for simplicity in construction.

To effect a print, an outside source (not shown) will energize theappropriate solenoids 169 which will cause a pull on the respectivewires 55. This foreshorting of a Wire 55 will pull the actuating section63 thereof in the direction of the arrow A (FIG. 3). As this occurs theloop around the corresponding stud 5S will move forward in the opening56 of the plate 52 as shown at 121i. As the loop moves forward it flexesthe respective tail 57 while at the same time driving the printingsection 54 out against a ribbon 122 to eiiect a print against the papersheet 200.

Upon deenergization of a solenoid `109 the correspending tail S7 will exback to its normal state allowing its wire to return to normal conditionand thus withdrawing its printing head section 54 back inside the plate52. It should be noted that each tail 57, when in its normal position,is actually prestressed slightly so that full return of the print wirewill be assured.

Each solenoid armature 112 is returned to its normal position by aspring 116 so that the respective tail 57 need only return its wire 55upon deenergization of the solenoid. This provides for a maximum speedof operation since the mass of each wire is relatively small.

After effecting a print, the magnet 43 of the clutch 18 will bemomentarily energized causing the clutch spring 33 to interconnectsleeves 34 and 35 to effect rotation of the hub 24 through onerevolution whereby the helical thread 27 will rotate the gear 2S onetooth stepping it over to the next indexing groove 17 so that the printhead will be advanced to the next character printing position.

In order to return the print head after it has traveled to the extremeleft hand end of the machine or to the end of a print line, a handle 121is fastened on the shaft 31 so that by rotating the handle 121 and shaft31 the gear 28 will move from its normally vertical position to ahorizontal position, as shown in dotted lines in FIG. 5 thereby freeingthe clutch assembly for manual axial movement.

' Upon release of the handle 121 the gear is returned by a torsionspring 123 into mesh with the thread 27 and the rack teeth 23 on theshaft 11.

An alternate form of actuator for the wires 55 is shown at 146 in FIGS.9 and 10, which uses a similar principle as that shown in U.S. Patent2,629,471 to J. Rabinow, wherein each lead wire or link 111 is attachedat 127 to an actuating arm 128 which is integrally formed on a hub 129which surrounds a continuously rotating shaft 131.

The hub 129 has on its inner periphery a relieved section 132 which isinlaid with two :half sections of iron 136 having low retentivitycharacteristics. The half sections are separated by two ridges 133integrally formed in the hub.

mossos Two grooves 138 and 139 are transversely formed on the outerperiphery of the hub 129 approximately 180 Iapart, which receiveopposite ends of a core member 141 of an electromagnet 142, the coremember being formed of a material having low retentive characteristicssuch as iron.

The hub 129 is preferably formed of a plastic material having highelasticity characteristics so thata tail section 143 of the hub, whichis retained by a pair of shafts 144 and 145, can be used as a returnspring for the actuator.

Rims 13d and 135 formed by the relieved section 132 of the hub hold thehub centered about the shaft 131 and also through an O-ring type seal151, intermediate the rim 134 of one unit and the rim 135 of theadjacent unit, retain a mixture of paramagnetic particles and a liquidsolution, such as a viscous oil, in a gap 137 between the inlaidsections 136 and the shaft 131.

Upon the application of a pulse to the coil 142 a magnetic flux pathwill be set up in the core 141, as shown by the dot-dash line 14S,passing through the plastic of the hub to the section 136 Where theparamagnetic particles will gather in the areas of most concentratedfiux lines, to form a bridge to the shaft 131 thereby passing throughthe shaft and baci; to the opposite side of the core in the same manneras above described.

The attraction between the shaft 131 and the section 136 will actuatethe hub in a counterclockwise direction and through the arm 123 and wire111 will actuate the respective wire 55'.

Although the invention has been described in detail and certain specificterms and languages have been used, it is to be understood that thepresent disclosure is illustrative rather than restrictive and thatchanges and modifications may be made Without departing from the spiritor scope of the invention as set forth in the claims appended hereto.

Having thus described the invention, what is desired to be secured byUnited States Letters Patent is:

1. A wire printing mechanism comprising means for supporting a recordmedium at a printing station, a guide plate adjacent said station, saidguide plate having a pair of first and second guideways therein, saidguideways extending in directions intersecting each other, said first-guideway being at -least substantially straight, a printing wire guidedfor endwise movement in said guideways, said Wire being bent back uponitself to -iorm a first section slideable in` said first guideway and asecond section slideable in said second guideway, said first sectionterminating lin a print head, a spring element on said plate, them-ovable portion of said spring element being connected to said wireintermediate said first and second sections thereof, :and said secondwire section being effective when pulled through said second -guidewayto push said first wire section along said first guideway .against theaction of said spring element whereby to project said print head againstsaid record medium at said printing station.

2.. A wire printing machine according to claim 1 wherein said movableportion of said spring is located adjacent said inter-section of saidguideway directions.

3. A wire printing mechanism comprising means Ifor supporting :a recordmedium at a printing station, a guide plate adjacent said station, saidguide plate having a first and second guid-eway therein, said firstguideway being at least substantially straight, said plate having anopening therein at one end of said first and second guideway, a printingwire guided for endwise movement in said guide- Ways, said wire beingbent back upon itself to form a first section slideable in said firstguideway and a second section slideable in said second guideway, saidfirst section terminatin g in a print head, a spring element integralwith said plate, the movable portion of said spring element extend* inginto said opening and engaging said wire .intermediate said first andsecond sections, and said second wire section being effective whenpulled through said second guideg -way to push said first wire sectionalong said first guideway against the action of said spring elementwhereby to project said print head -toward said record medium at .saidprinting station.

4. A wire printing mechanism comprising means for supporting a recordmedium at a printing station, a guide plate adjacent said station, saidguide plate having a plurali-ty of pairs of first and second guidewaystherein, said first guideway being at least substantially straight, theguideways of each of said pairs lying in at least substantially the sameplane and intersecting each other, printing Wires guided for endwisemovement in respective ones of said pairs of guideways, each of saidwires 'being bent back upon itself to form a first section slideable ina said first guideway and a second section slideable in la said secondguideway, each of said first sections terminating in a print head,spring elements on said plate, the movable portion of each of saidspring elements engaging a respective one of said wires intermediatesaid first and second sections thereof, and each of said second wiresections being effective when pulled through a said second guideway topush the respective said first wire section along said first guide- Wayagainst the action of .a respective said spring element whereby toproject a respective said print head tow-ard said record medium at saidprinting station.

5. A wire printing mechanism comprising means for supporting a recordmedium lat a printing station, a guide plate adjacent said station, saidguide plate having a plurality of pairs of tirst and second guidewaystherein, said first guideways being at least substantially straight, theguideways of each of said pairs lying in at least substantially the sameplane, said guideways of each of said pairs extending in directionsintersecting each other, said plate having an opening therein adjacenteach of said intersections, printing wires guided for endwise movementin re spective ones of said .pairs of guideways, each of said wiresbeing bent back upon itself to form a first section slideable in a saidfirst guideway and a second section slideable in a said second guideway,each of said first sections terminating in a print head, spring elementsintegral with said plate and extending into respective ones of saidopenings, the movable portion of each of said spring elements engaging arespective one of said wires intermediate said first Iand second sectionthereof, and each of said second wire t sections being effective whenpulled through a said second guideway to push the respective said firstwire section along said first guideway against the action of :arespective said `spring element whereby to project a respective printhead against said record medium at said printing station.

A 4wire printing mechanism comprising means -for supporting a recordmedium `at a printing station, a guide plate adjacent said station, saidguide plate having a plura'lity of pairs of first and second guidewaystherein, said first guideway being at least substantially straight, theguideways of each of said pairs intersecting each other, said platehaving an opening therein adjacent each of said intersections, printingwires guided for endwise movement in respective ones of said pairs ofguideways, each of said wires being -bent bach upon itself to form afirst section slideable in a said first guideway and a second sectionslideable in a said second guideway, each of said first sectionsterminating in a print head, spring elements integral with said plate,the movable portion of each of said spring elements extending into arespective one oi said openings, each of said wires being looped arounda respective one of said spring elements, and each of said second Wiresections being effective when pulled through a said second guideway topush a respective said first wire section along said first guidewayI'against the action of a respective said spring element whereby toproject a respective print head toward said record medium at saidprinting station.

1'7. A wire printing mechanism according to claim 6 wherein ysaid firstguideways converge toward each other adjacent said printing station.

`8. A Wire printing mechanism `comprising means for supporting a recordmedium at a printing station7 a plurality of guide plates in face toface relation with each lother adjacent said station, each of said guideplates having a plurality of pairs of first .and second guidewaystherein, each of said guideways in certain ones of said plates beingcovered by the face of an adjoining said plate, the guideways of each ofsaid pairs extending in directions intersecting each other, said plateseach 'having an opening therein adjacent each of said intersections,printing wires guided for endwise movement in respective ones of saidpairs of guideways, each of said wires being lbent back upon itself toform a first section slidea'ble in a said first guideway and a secondsection slidea'ble in a said second guideway, each of said firstsections terminating in a print head, spring elements integral with saidplates, the mov- `alble portion of each of said spring elementsextending into a respective one of said 4openings and engaging arespective one of said wires intermediate said first and second sectionsthereof, each of said second wire sections fbeing effective when pulledthrough a said second guideway to push a respective said first wiresection along said first guideway against the action of a respectivesaid spring eiement whereby to project a respective print head towardsaid record medium at said printing sta-tion, `and said first guidewaysbeing at least substantially straight and converging toward each otheradjacent said printing station.

9. A wire printing mechanism comprising means for support-ing a recordmedium at a printing station, a plutrality of guide plates in face toface relation with each other adj-acent said station, each of saidplates tapering in thickness toward a common end thereof, each of saidplates having a plurality of pairs of first and second guidewaystherein, each of said guideways in certain ones of said plates beingcovered by the tace of an adjoining said plate, the guideways of each ofsaid pairs extending in directions intersecting each other, printingwires guided for endwise movement in respective ones of said pairs ofguideways, each of said Wires being bent back upon itself to -form afirst section slideable in a said first'guideway and a second sectionslideable in a said second guideway, each of said first sectionstermin-ating in a print he-ad, spring elements `carried by said plates,the movable portion of each of said spring elements engaging arespective one of ysaid wires intermediate said first and secondsections thereof, and each of said wires sections being effective whenpulled through a said second guideway to push a respective said firstwire section along the respective first guideway toward said common endagainst the action of a respective said spring element whereby toproject a respective print head toward said record medium at saidprinting station.

10. Printing mechanism comprising a frame, means on said fr-ame forsupporting a record medium at a printing station, a carriage movablerelative to said frame and along said printing station into differentpositions, a wire, said wire 'being bent back upon itself to form afirst and Second section, said first section terminating in a printhead, means on said carriage `for guiding said first section for endwisemovement toward and away from said printing station, means on saidcarriage `for guiding a portion of said second section adjacent saidfirst section for endwise movement whereby pulling of said secondsection will push said first section toward said printing station, meanson said frame guiding said second section for endwise movement in aloop, means anchoring the end of said second sectionopposite said firstsection to said carriage, and means Afor transversely defiecting aportion of said second section in different positions of said carriagewhereby to push said first section toward said printing station.

1.1. Printing mechanism according to claim 10 comprising spring meanscarried by said carriage `for yieldabiy maintaining said first wiresection away from said printing station.

12. Printing mechanism comprising .a frame, means on said .frame `forsupporting a record medium at a printing station, a carriage movablerelative to said frame and along said printing station into differentpositions, a plurality of wires, said wires each being bent back uponitself to form a first and second section, said first sectionsterminating in print heads, means on said carriage for guiding saidfirst sections for endwise movement toward and away from said printingstation, said guide means causing said first section to converge towardeach other adjacent said printing station, means on said carriage forguiding portions of said second sections adjacent said first sectionsfor endwise movement whereby pulling of said second sections will pushrespective ones of said first sections toward said printing station,means on said frame independently guiding said second sections forendwise movement in loops, means .anchoring the ends of said secondsections opposite said first sections to said carriage, and means -fortransversely defiecting portions of selected ones of said secondsections in different positions of said carriage whereby to pushrespective ones of said first sections toward said printing station.

References Cited by the Examiner UNITED STATES PATENTS 1,028,037 5/12Lilleberg 1971 I1,078,081 1'1/13 Baker 197-'12 2,129,065 9/38 Loop 197-12,653,534- 9/53 Wockenfuss lOl-93 2,708,020 5/55 Wockenfuss 197-12,802,414 8/57 Johnson 197-1 V2,891,648 6/59 Kleinschmidt 197-122,911,085 11/59 Leathers 197-1 2,928,338 3/60 Wockenfuss 10i- 932,997,152 8/61 Dirks 197-1 3,087,420 4/63 Brehm 101-93 WILLlAM B. PENN,Primary Examiner.

1. A WIRE PRINTING MECHANISM COMPRISING MEANS FOR SUPPORTING A RECORDMEDIUM AT A PRINTING STATION, A GUIDE PLATE ADJACENT SAID STATION, SAIDGUIDE PLATE HAVING A PAIR OF FIRST AND SECOND GUIDEWAYS THEREIN, SAIDGUIDEWAYS EXTENDING IN DIRECTIONS INTERSECTING EACH OTHER, SAID FIRSTGUIDEWAY BEING AT LEAST SUBSTANTIALLY STRAIGHT, A PRINTING WIRE GUIDEDFOR ENDWISE MOVEMENT IN SAID GUIDEWAYS, SAID WIRE BEING BENT BACK UPONITSELF TO FORM A FIRST SECTION SLIDEABLE IN SAID FIRST GUIDEWAY AND ASECOND SECTION SLIDEABLE IN SAID SECOND GUIDEWAY, SAID FIRST SECTIONTERMINATING IN A PRINT HEAD, A SPRING ELEMENT ON SAID PLATE, THE MOVABLEPORTION OF SAID SPRING ELEMENT BEING CONNECTED TO SAID WIRE INTERMEDIATESAID FIRST AND SECOND SECTION THEREOF, AND SAID SECOND WIRE SECTIONBEING EFFECTIVE WHEN PULLED THROUGH SAID SECOND GUIDEWAY TO PUSH SAIDFIRST WIRE SECTION ALONG SAID FIRST GUIDEWAY AGAINST THE ACTION OF SAIDSPRING ELEMENT WHEREBY TO PROJECT SAID PRINT HEAD AGAINST SAID RECORDMEDIUM AT SAID PRINTING STATION.